Hitachi SJ300 Series Output Deviation for PID Control

4–47

SJ300 Inverter

Output Deviation for PID Control

The PID loop error is defined as the magnitude (absolute value) of the difference between the Setpoint (target value) and the Process Variable (actual value). When the error magnitude exceeds the preset value for C044, the [OD] terminal signal turns ON. Refer to “PID Loop Operation” on page 4–71.

	Error			Process variable
(SP-PV)
					Setpoint
Set		C044
value		C044
		[OD]
		Signal	ON			ON
							t

Opt.

Symbol

Function Name

Output

Description

Code

State

04

OD

Output deviation

ON

when PID error is more than the set

for PID control

threshold for the deviation signal

OFF

when PID error is less than the set thresh-

old for the deviation signal

Valid for

11, 12, 13, 14, 15,

Example: (Requires output configuration—

outputs:

AL0 – AL2

see page 3–53):

Required

C044

Inverter output terminal circuit

settings:

OD

Notes:

• The default deviation value is set to 3%. To

change this value, change parameter C044

14

13

11

(deviation level).

15

CM2

12

+

RY –

See I/O specs on page 4–9.

Operations Monitoring and

NOTE: The example circuit in the table above drives a relay coil. Note the use of a diode to prevent the negative-going turn-off spike generated by the coil from damaging the inverter’s output transistor.